Insulated Gate Bipolar Transistor (IGBT) is a widely used semiconductor device. In an IGBT, when a predetermined voltage is applied to a gate electrode thereof, electrons are supplied from an emitter region to a drift region and holes are supplied from a collector region to the drift region. Due to the electrons and the holes supplied to the drift region, an ON voltage is reduced by modulating the conductivity modulation of the drift region. However, the IGBTs may experience a reduction in their withstand voltage when they are designed to have a reduced ON voltage.